Bun support

[Dimava]

I'm trying to use this with Bun to make a sync Prettier implementation (as the @prettier/sync sync runner crashes because bun doesn't support stdio in workers yet)

Bun has builtin TS support so I need either a "bun" tsRunner or allow TS in bun when tsRunner is undefined

(I'm not sure about 2nd one, because it may lead to confusion when trying to use the same code in Node)

edit: renamed to "Bun TS support" as JS works fine